Bangor’s planning board approved the St. Joseph Healthcare’s site development plan for a 22,700-square-foot medical office building during a Tuesday night meeting.

Lois Macias, St. Joseph Healthcare’s vice president of integrated care and physician practices, said the roughly $6 million building will be built at 900 Broadway, the address of a health care park that’s already home to four office buildings owned by the system.

The hospital hopes to begin construction in September, allowing the offices to open for business next summer, according to Macias. The building will house 20 practitioner offices, according to St. Joseph officials. Of those practices, 18 are already working at the site in other buildings. The space those practitioners vacate will be filled in later with expansions or for other medical purposes, according to project plans.

Earlier this month, Eastern Maine Medical Center received approval for a 30,000-square-foot, two-story medical office building in the Maine Business Industrial Park off Maine Avenue. The $5.25 million expansion will help EMMC house a growing number of physicians and nurses, according to hospital officials.

Macias said St. Joseph Healthcare’s new one-story building will house offices of primary care providers for both adults and families, as well as space for providers specializing in health services ranging from geriatrics to osteoporosis treatment.

St. Joseph, like other hospitals across the nation, is shifting to a health care model that focuses on keeping more people out of the hospital, according to Macias.

“The focus is a lot more on prevention,” she said. “It’s about partnering with patients and families to keep them healthy.”

Also this year, St. Joseph Healthcare plans to start just over $3 million in upgrades and improvements to its hospital. The emergency department will be expanded, and “patient flow” will be improved, according to Macias. The endoscopy and other units in the hospital also will be expanding and rearranging. The emergency department portion of the project is expected to wrap up this winter, with other projects stretching into next fall.

“We’re just excited to get started and make this available to our patients,” Macias said.

Correction:The headline of this story listed the expansion as $5.25 million. It is $6 million.